Overview

Adding a co-borrower to a mortgage application combines both borrowers incomes and debts for DTI purposes. When one borrower has insufficient income or too-high DTI, adding a co-borrower with income and low debt can transform a denial into an approval. Understanding how co-borrower DTI works guides who to add and when.

💡Key Insight

Adding a co-borrower to a mortgage application combines both borrowers incomes and debts for DTI purposes. When one borrower has insufficient income or too-high DTI, adding a co-borrower with income and low debt can transform a denial into an approval. Understanding how co-borrower DTI works guides who to add and when.

Key Points

  • Co-borrower income is added to the numerator in DTI; co-borrower debts are added to the denominator
  • A co-borrower with high income and low debt dramatically improves the combined DTI ratio
  • Non-occupant co-borrowers (parents helping adult children) are allowed on many loan programs
  • Co-signer and co-borrower have different legal responsibilities -- understand the distinction
  • Adding a co-borrower with existing high debt may worsen your DTI if their debt-to-income is poor

Calculate Your DTI

Use the debt-to-income calculator to see your current DTI and determine how much debt or income change is needed to reach your qualification target.

Calculate Your Debt-to-Income Ratio

Enter your income and monthly debt payments to see your front-end and back-end DTI ratios instantly.

Open Debt-to-Income Calculator →